One questionnaire - two points in time: Has plant species knowledge of laypeople changed over a period of 20 years?

Concern has been raised that in recent decades knowledge of plant species has severely declined in western countries. However, in the absence of regularly repeated and standardized surveys, no reliable statement can be made as to whether plant species knowledge has actually declined in recent decades. The present study aimed to contribute to filling this knowledge gap by repeating a survey on the knowledge of plant species twenty years later. Laypeople (all adults) were asked to identify 15 common wild plant species of Germany, which were presented to them as photographs. Based on previous research, five of the 15 species were considered well-known, five moderately known, and five rather unknown to laypeople. The original survey was conducted in 2002 at two locations in the city of Marburg, while its repetition took place in 2022/23, both in Marburg (identical location) and the city of Freiburg, as well as online. In total, 1558 individuals (18-88 years old) participated in the surveys...., , # Data from: One questionnaire - two points in time: Has plant species knowledge of laypeople changed over a period of 20 years? Dataset DOI: [10.5061/dryad.931zcrk1p](https://doi.org/10.5061/dryad.931zcrk1p) ## Description of the data and file structure Data for publication \"Petra Lindemann-Matthies, Theresa Gellesch , Diethart Matthies (2026): One questionnaire - two points in time: has plant species knowledge of laypeople changed over a period of 20 years? - People and Nature. ### Files and variables #### File: Species_Publication.xlsx **Description:**Â One line for each combination of person and plant species ##### Variables. See File: Explanation_of_variables.pdf <br /> #### File: Data_Publication.xlsx **Description:**Â One person per line and performance ##### Variables. See File: Explanation_of_variables.pdf <br /> #### File: Explanation_of_variables.pdf **Description:**Â PDF list of variables with descriptions. , We received explicit consent from your participants to publish the de-identified data in the public domain. The data do not allow to identify individual persons.,